Gelatin-based hemostats, both in solid sponge or powder form, are commercially available and are used in surgical procedures. Gelatin powder, when mixed with fluid, can be prepared in various forms depending on the contemplated end-use and the ratio of fluid to powder. For example, where higher concentrations of fluid are employed, a paste or slurry that is useful as a flowable, extrudable and injectable hemostat may be prepared for use in diffuse bleeding, particularly from uneven surfaces or hard to reach areas. Such conventional slurries are prepared at the point of use by mechanical agitation and mixing of the powder and liquid to provide uniformity of the composition. The paste then is placed into a delivery means or applicator, e.g. a syringe, and applied to the wound. In other cases, moldable compositions may be prepared with lower amounts of fluid and molded or packed to form a dressing for use on external wounds. Gelatin powders are sterilized prior to preparing such compositions but mixing of the powders and fluids may compromise the sterility of the hemostatic composition due to handling of the materials at the site of use, or in general by exposure to the environment for relatively extended periods of time during mixing and the like.
Thrombin that is not terminally sterilized is known to be used in combination with such hemostatic compositions. Proteins such as thrombin are prepared aseptically and thus there is a risk that nonsterilized proteins such as thrombin, when used in hemostatic compositions, may compromise the sterility of the previously-sterilized materials, such as sterilized gelatin powder. However, as thrombin is known to be denatured by exposure to sterilizing condition such as ionizing radiation conventionally used to sterilize the powders, which denaturing destroys all enzymatic activity of the thrombin, thrombin has not been reported to be incorporated into the hemostatic compositions and then terminally sterilized prior to use to ensure a sterile composition. In fact, when thrombin is used in conventional hemostatic compositions, nonsterilized thrombin is added after sterilization of hemostatic composition.
It would be desirable if a sterile hemostatic composition containing active sterile thrombin was available to the surgeon at the point of use without need for preparation, e.g. without having to add thrombin prior to use. The compositions of the present invention fulfill that need.